Improving Covariance Based Adaptive Estimation for GPS/INS Integration

Weidong Ding,Jinling Wang,Chris Rizos 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-

It is well known that the uncertainty of the covariance parameters of the process noise (Q) and the observation errors (R) has a significant impact on Kalman filtering performance. Q and R influence the weight that the filter applies between the existing process information and the latest measurements. Errors in any of them may result in the filter being suboptimal or even cause it to diverge. The conventional way of determining Q and R requires good a priori knowledge of the process noises and measurement errors, which normally comes from intensive empirical analysis. Many adaptive methods have been developed to overcome the conventional Kalman filter’s limitations. Starting from covariance matching principles, an innovative adaptive process noise scaling algorithm has been proposed in this paper. Without artificial or empirical parameters to be set, the proposed adaptive mechanism drives the filter autonomously to the optimal mode. The proposed algorithm has been tested using road test data, showing significant improvements to filtering performance.

Time Synchronization Error and Calibration in Integrated GPS/INS Systems

Weidong Ding,Jinling Wang,Yong Li,Peter Mumford,Chris Rizos 한국전자통신연구원 2008 ETRI Journal Vol.30 No.1

The necessity for the precise time synchronization of measurement data from multiple sensors is widely recognized in the field of global positioning system/inertial navigation system (GPS/INS) integration. Having precise time synchronization is critical for achieving high data fusion performance. The limitations and advantages of various time synchronization scenarios and existing solutions are investigated in this paper. A criterion for evaluating synchronization accuracy requirements is derived on the basis of a comparison of the Kalman filter innovation series and the platform dynamics. An innovative time synchronization solution using a counter and two latching registers is proposed. The proposed solution has been implemented with off-the-shelf components and tested. The resolution and accuracy analysis shows that the proposed solution can achieve a time synchronization accuracy of 0.1 ms if INS can provide a hard-wired timing signal. A synchronization accuracy of 2 ms was achieved when the test system was used to synchronize a low-grade micro-electromechanical inertial measurement unit (IMU), which has only an RS- 232 data output interface.

Facile synthesis of luminescent and amorphous La2O3-ZrO2:Eu(3+) nanofibrous membranes with robust softness.

Han, Weidong,Ding, Bin,Park, Mira,Cui, Fuhai,Ghouri, Zafar Khan,Saud, Prem Singh,Kim, Hak-Yong RSC Pub 2015 Nanoscale Vol.7 No.34

<P>Novel luminescent and amorphous La2O3-ZrO2:Eu(3+) (LZE) nanofibrous membranes with robust softness are fabricated for the first time via a facile electrospinning technique. By incorporating zirconium oxide, the as-prepared lanthanum oxide nanofibrous membranes can be dramatically changed from extreme fragility to robust softness. Meanwhile, the softness and luminescent performance of LZE nanofibrous membranes can be finely controlled by regulating the doping concentration of zirconium oxide and europium in lanthanum oxide nanofibers. Additionally, the crystal structure analysis using X-ray diffractometer and high resolution transmission electron microscopy measurements have confirmed the correlation between the amorphous structure and softness. Furthermore, LZE membranes show the characteristic emission of Eu(3+) corresponding to (5)D0, 1, 2-(7)F0, 1, 2, 3, 4 transitions due to an efficient energy transfer from O(2-) to Eu(3+). The LZE nanofibrous membranes with the optimum doping Eu(3+) concentration of 3 mol% exhibit excellent softness and luminescent properties, which make the materials to have potential applications in fluorescent lamps and field emission displays.</P>

Insight into the precursor nanofibers on the flexibility of La₂O₃-ZrO₂ nanofibrous membranes

Han, Weidong,Ding, Bin,Park, Mira,Cui, Fuhai,Chae, Su-Hyeong,Kim, Hak-Yong De Gruyter 2017 E-Polymers Vol.17 No.3

<P><B>Abstract</B></P><P>Poly(vinyl pyrrolidone) (PVP)/La<SUP>3+</SUP>/Zr<SUP>4+</SUP>precursor nanofibrous membranes (LZPNM) with various Zr contents were synthesized via a simple electrospinning method. By controlling the Zr incorporation, the tensile properties of precursor membranes dramatically change from 0.77 to 1.73 MPa. Meanwhile, the average diameters of precursor nanofibers increase with the increase of Zr contents (from 283 to 535 nm). In addition, flexible La<SUB>2</SUB>O<SUB>3</SUB>-ZrO<SUB>2</SUB>nanofibrous membranes (LZNM) were obtained by calcination of corresponding precursor membranes. Furthermore, the structures and morphologies of the precursor membranes were investigated using X-ray powder diffraction analysis (XRD) and field-emission scanning electron microscopy (FE-SEM). The surface functional groups and thermal properties of the precursor membranes were measured via Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA).</P>

Utility and Collaborative Filtering-Based Evaluation Method

Xiaolong Zhu,Weidong Zhu,Shuai Ding 보안공학연구지원센터(IJUNESST) 2013 International Journal of u- and e- Service, Scienc Vol.6 No.4

Naloxone Postconditioning Alleviates Rat Myocardial Ischemia Reperfusion Injury by Inhibiting JNK Activity

Anzhou Xia,Zhi Xue,Tan Zhang,Tiantian Wei,Xingzhi Sha,Yixun Ding,Weidong Zhou 대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.1

To investigate the alteration of c-Jun N-terminal kinase (JNK) activity after myocardial ischemiareperfusion injury (MIRI) and further explore the effect of naloxone postconditioning on MIRI. Fortymale Sprague Dawley rats were randomly divided into five groups: sham operation (sham, n=8);ischemia reperfusion (IR, n=8); IR+naloxone 0.5 mg/kg (Nal L, n=8); IR+naloxone 1.0 mg/kg (Nal M,n=8); IR+naloxone 2.0 mg/kg (Nal H, n=8). Pathological changes of myocardial tissue were visualizedby HE staining. The expression of p-JNK, and the apoptosis of cardiomyocytes were investigated withWestern blotting and the TUNEL assay, respectively. Irregular arrangement and aberrant structureof myocardial fibers, cardiomyocytes with granular or vacuolar degeneration, and inflammatory cellsinfiltrating the myocardial interstitial regions characterized MIRI in the IR group. Signs of myocardialinjury and inflammatory infiltration were less prominent in the Nal-treated groups. The expressionof p-JNK in the sham group and in all Nal-treated groups was significantly lower than that in theIR group (p<0.01). The apoptosis index of cardiomyocytes in the IR group was significantly higherthan in the sham group (p< 0.01). The apoptosis indices of cardiomyocytes in all Nal-treated groupswere significantly reduced to 55.4%, 26.2%, and 27.6%, respectively, of the IR group (p< 0.01). Thisstudy revealed that Naloxone postconditioning before reperfusion inhibits p-JNK expression anddecreases cell apoptosis, thus alleviating MIRI.

Naloxone Postconditioning Alleviates Rat Myocardial Ischemia Reperfusion Injury by Inhibiting JNK Activity

Xia, Anzhou,Xue, Zhi,Wang, Wei,Zhang, Tan,Wei, Tiantian,Sha, Xingzhi,Ding, Yixun,Zhou, Weidong The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.1

To investigate the alteration of c-Jun N-terminal kinase (JNK) activity after myocardial ischemia reperfusion injury (MIRI) and further explore the effect of naloxone postconditioning on MIRI. Forty male Sprague Dawley rats were randomly divided into five groups: sham operation (sham, n=8); ischemia reperfusion (IR, n=8); IR+naloxone 0.5 mg/kg (Nal L, n=8); IR+naloxone 1.0 mg/kg (Nal M, n=8); IR+naloxone 2.0 mg/kg (Nal H, n=8). Pathological changes of myocardial tissue were visualized by HE staining. The expression of p-JNK, and the apoptosis of cardiomyocytes were investigated with Western blotting and the TUNEL assay, respectively. Irregular arrangement and aberrant structure of myocardial fibers, cardiomyocytes with granular or vacuolar degeneration, and inflammatory cells infiltrating the myocardial interstitial regions characterized MIRI in the IR group. Signs of myocardial injury and inflammatory infiltration were less prominent in the Nal-treated groups. The expression of p-JNK in the sham group and in all Nal-treated groups was significantly lower than that in the IR group (p<0.01). The apoptosis index of cardiomyocytes in the IR group was significantly higher than in the sham group (p<0.01). The apoptosis indices of cardiomyocytes in all Nal-treated groups were significantly reduced to 55.4%, 26.2%, and 27.6%, respectively, of the IR group (p<0.01). This study revealed that Naloxone postconditioning before reperfusion inhibits p-JNK expression and decreases cell apoptosis, thus alleviating MIRI.